Roofing system and method for preparing the same

ABSTRACT

A roof system comprising a roof deck, an insulation layer, a coverboard disposed over said insulation layer, where said coverboard includes a foam core and a facer including a fibrous mat and an interfacial region disposed between said core and said mat, and a layer of asphalt.

This application claims the benefit of U.S. Provisional Application Ser.No. 61/864,110, filed Aug. 9, 2013, which is incorporated herein byreference.

FIELD OF THE INVENTION

Embodiments of the invention are directed toward roofing systems andmethods for preparing the same wherein polyisocyanurate cover boards areemployed.

BACKGROUND OF THE INVENTION

In the roofing art, particularly in the covering of flat or low-slopedroofs, built-up roofing (BUR) systems may be employed. One commontechnique for preparing a BUR system includes the use of a liquidasphaltic material, which is made liquid by heating the asphalticmaterial to at least a temperature where the asphaltic material flows.In this regard, reference may be made to hot asphalt. As is generallyknown in the art, one or more reinforcing fabrics may be applied to theroof surface in conjunction with one or more applications or coatings ofthe hot asphalt. Also, reflective materials, such as rocks, aretypically applied over the asphaltic surface, which is formed byapplication of the hot asphalt, in order to protect the asphalticsurface from solar radiation.

While the roof surface, which may also be referred to as a roof deck, towhich the asphaltic material is applied, may include robust materialssuch as wood or concrete, it is often the situation where one or morelayers of insulation are applied to the roof deck prior to applicationof the hot asphalt. The insulation is often in the form of cellularinsulation boards or panels, such as polyisocyanurate or polystyreneinsulation boards. These insulation boards, however, do not have thethermal stability to withstand the heat associated with the hot asphalt,which could exceed temperatures of 260° C. during application.

In view of this shortcoming, it is often required to place protectionover the insulation prior to application of the hot asphalt. Forexample, fiberglass-backed gypsum board is often applied to cover theinsulation board and, among other things, protect the insulation boardfrom the heat of the hot asphalt.

One shortcoming of the fiberglass-backed gypsum board is its weight,which can be a significant factor impacting the speed and cost ofinstallation. While high-density polyisocyanurate boards have grown inpopularity as insulation coverboards due to their light weight andinstallation ease, these boards have proven inferior in protectinginsulation during installation of a BUR system since thesepolyisocyanurate cover boards are themselves suspect to damage ordistortion from the heat of the hot asphalt.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provides a roof systemcomprising a roof deck, an insulation layer, a coverboard disposed oversaid insulation layer, where said coverboard includes a foam core and afacer including a fibrous mat and an interfacial region disposed betweensaid core and said mat, and a layer of asphalt.

One or more embodiments of the present invention provides a method forinstalling a roof system, the method comprising applying a layer ofcoverboards to a layer of insulation, where the coverboards include afoam core and a facer including a fibrous mat and an interfacial regiondisposed between said core and said mat and applying a liquefiedhot-melt sealant directly to the coverboard.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional, fragmentary view of a building structurehaving a roof system according to one or more embodiments of the presentinvention.

FIG. 2 is a fragmentary perspective view of a coverboard employed in thepractice of one or more embodiments of the present invention.

FIG. 3 is a cross-sectional view of a coverboard employed in thepractice of one or more embodiments of the present invention.

FIG. 4 is a cross-sectional view of a coverboard employed in thepractice of one or more embodiments of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the invention are based, at least in part, on thediscovery of a polyisocyanurate coverboard that is useful in protectinginsulation board during installation of a hot sealant material (e.g. hotasphalt), such as used to create a built-up roof system. In one or moreembodiments, the cover board includes a polyisocyanurate foam corehaving a relatively high density and a facer including a fibrous mat,wherein an interfacial region is disposed between the foam core and themat. It has unexpectedly been discovered that the combination of therelatively high density core and the interfacial region between the matand the foam core provides a coverboard that can withstand the thermalstresses of a hot sealant. Advantageously, these coverboards can be usedwith hot sealant materials to not only protect the underlying insulationlayers, but the coverboards themselves are not deleteriously impacted.Accordingly, embodiments of the invention are directed toward a roofsystem that includes a coverboard and a layer of asphalt applied to thecoverboard, as well as methods for producing the same.

Roof System

A built-up roof system according to embodiments of the invention can bedescribed with reference to FIG. 1, which shows a building structure 10having a roof system 13 including a roof deck 15, an insulation layer17, a coverboards 19, and a built-up roof 21, which may also be referredto as BUR 21. While embodiments of the invention are described withrespect to a built-up roof system, the invention is not limited to anyspecific type of built-up roof system. Instead, practice of theinvention is applicable to any roofing situation wherein hot asphalt isapplied. BUR 21 may include a first sealant layer 23, optionalreinforcing fabric 25, optional second sealant layer 27, and optionalreflective or protective material 29. Coverboards 19, as will bedescribed in greater detail herein, include a foam core and at least onefacer including a fibrous mat and an interfacial region disposed betweenthe mat and the core. This at least one mat is disposed on at leastupper planar surface 20 of coverboard 19 and is thereby adjacent tofirst sealant layer 23. As is known in the art, BUR 21 may includemultiple reinforcing fabrics and multiple sealant layers (not shown),and it is understood that these multiple layers derive from multipleapplications of liquid sealant compositions. Also, the roof system mayinclude multiple reinforcements (not shown) deriving from multipleapplications or layers of reinforcing fabric applied between themultiple applications of molten sealant material. In one or moreembodiments, the respective sealant layers are monolithic.

Roof Deck

Practice of this invention is not limited by the selection of anyparticular roof deck. Exemplary roof decks include concrete pads, steeldecks, wood beams, and foamed concrete decks.

Insulation Layer

Practice of this invention is likewise not limited by the selection ofany particular insulation board. As is known in the art, severalinsulation materials can be employed. In one or more embodiments, theinsulation is a foamed insulation board, which may be referred to as acellular insulation board. In one or more embodiments, the cellularinsulation includes polymeric struts or plates. For example, theseboards may include polyurethane, polyisocyanurate, blendedpolyurethane/polyisocyanurate, and polystyrene cellular materials.

In one embodiment, the insulation board comprises polyurethane orpolyisocyanurate cellular material. These insulation boards are known inthe art as disclosed in U.S. Pat. Nos. 6,117,375, 6,044,604, 5,891,563,5,573,092, U.S. Publication Nos. 2004/01099832003/0082365, 2003/0153656,2003/0032351, and 2002/0013379, as well as U.S. Ser. Nos. 10/640,895,10/925,654, and Ser. No. 10/632,343, which are incorporated herein byreference. In general, polyurethane is characterized by having an indexof from about 100 to about 120; polyisocyanurate is generallycharacterized by having an index that is in excess of 150 (in otherembodiments at least 175, and in other embodiments at least 200; andinsulation with an index between 120 and 150 generally includes a mix ofpolyurethane and polyisocyanurate.

In those embodiments where the insulation layer comprises polyurethaneor polyisocyanurate cellular material, these cellular materials may bedefined by a foam density (ASTM C303) that is less than 2.5 pounds percubic foot, in other embodiments less than 2.0 pounds per cubic foot, inother embodiments less than 1.9 pounds per cubic foot, and still inother embodiments less than 1.8 pounds per cubic foot. In one or moreembodiments, these polyurethane or polyisocyanurate insulation layersmay also be characterized by having a density that is greater than 1.50pounds per cubic foot and optionally greater than 1.55 pounds per cubicfoot.

CoverBoard Configuration of Board

A coverboard according to one or more embodiments is depicted in FIG. 2.Board 30 includes a cellular body or foam core 31, which may generallyhave a planar shape, and includes first planar surface 32 and secondplanar surface 34. Foam core 31 may also be characterized by a thickness40, a length 36, and a width 38. Length 36 and width 38 of board 30 mayvary, and these embodiments are not necessarily limited by the selectionof a particular length or width. Nonetheless, because these boards areadvantageously employed in the construction industry, board 10 may besized to a 4′×8′ sheet (e.g., 3.75′×7.75′), a 4′×10′ sheet, or a 4′×4′sheet. The thickness 40 of the foam core can generally be greater thanabout 0.25 inches, and may be from about 0.5 to 6.0 inches or in otherembodiments from about 1.0 to 4.0 inches in thickness.

Board 30 includes a first facer 42, which can be positioned adjacent oneof the first or second planar surfaces 32 or 34. For example, as shownin FIG. 2, facer 42 may be positioned adjacent second planer surface 32.In one or more embodiments, facer 42 can be integral with planar surfaceto which it is adjacent as a result of the methods employed tomanufacture board 30, which will be disclosed below.

As also shown in FIG. 2, board 30 may also include a second optionalfacer 43 positioned adjacent the planer surface opposite the planarsurface on which facer 42 is positioned. For example, facer 42 ispositioned adjacent second planer surface 32, and facer 43 is positionedadjacent first planer surface 34. Facer 43 can include the same ordifferent materials or compositions, as well as the same or differentthickness as facer 42.

As shown in FIG. 3, at least one of the facers (e.g. facer 42 and/orfacer 43) includes a mat 46 and a coating layer 48. Mat 46 may also bereferred to as fabric 46. Coating layer 48 may also be referred to asinterfacial region 48, and comprises coating material. The coatingmaterial may also be dispersed in interstices that exist within mat 46,and this coating material may generally be referred to as penetratedcoating material 50. As shown in FIG. 4, at least one of the facers(e.g. facer 42 and/or facer 43) includes first coating layer 60 andsecond coating layer 62, as well as mat 46 and penetrated coatingmaterial 66.

Mat

As described above, one or more of the facers employed in practicingthis invention (e.g. facer 42 and/or facer 43) includes a mat (e.g. mat46). In one or more embodiments, the mat is a non-woven inorganic mat.Exemplary types of non-woven mat include fiberglass mats, which may alsobe referred to as glass mats. In one or more embodiments, the non-wovenfiberglass mats include include glass fibers and a binder which bindsthe glass fibers together and maintains the fibers in a mat form. Anytype of glass fiber mat can be used in the composite board. For example,a non-woven glass fiber mat can be made with glass fibers and bondedwith an aqueous thermosetting resin such as, for example, ureaformaldehyde or phenolic resole resins.

In one or more embodiments, the dimensional and weight characteristicsof the glass fiber mat are not particularly limited, and can depend onthe specific application and desired properties of the coverboard. Forexample, the basis weight of the glass fiber mat 46 can be from about 50grams per square meter to about 150 grams per square meter. Thethickness of the glass fiber mat 46 can be, for example, from about0.015 inch to about 0.05 inch. The basis weight and thicknesscharacteristics can be adjusted depending upon the desired rigidity,strength and weight of the composite board.

The thickness of the facer material may vary; for example, it may befrom about 0.01 to about 1.00 or in other embodiments from about 0.015to about 0.050 inches thick.

Coating Material

As described above, one or more of the facers employed in practicingthis invention (e.g. facer 42 and/or facer 43) includes one or morecoating layers (e.g. coating layer 60 or 62), as well as coatingmaterial disposed within the interstices of the mat, which coatingmaterial is referred to as penetrated coating material 66.

In one or more embodiments, the coating layers, as well as the coatingmaterial, include a binder and an inorganic filler. The binder bonds theinorganic filler together and additionally bonds the inorganic filler tothe glass fiber mat. The binder can be polymeric and derive from, forexample, a latex binder, a starch or combinations thereof. Examples oflatex binders include butyl rubber latex, styrene butadiene rubber (SBR)latex, neoprene latex, acrylic latex and SBS latex, and can inparticular include the SBR latex. In one embodiment, each of the firstand second binding compositions can include from about 1% latex to about15% latex, based on the respective weight of each binding composition.In another embodiment, each of the first and second binding compositionscan include from about 1% latex to about 5% latex, based on therespective weight of each binding composition. Examples of a suitableinorganic filler include calcium carbonate, clay, talc, mica, perlite,hollow ceramic spheres or a combination thereof. In an exemplaryembodiment, the inorganic filler can include calcium carbonate. In anexemplary embodiment, the inorganic filler can be present in the firstand second binding compositions in an amount from about 80% to about98%, based on the respective weight of each composition.

In one or more embodiments, the coating layers (e.g. layers 60 and 62),as well as the penetrated coating material, allow for a relatively highdegree of air permeability of the facer. In one or more embodiments, thecoating layers are discontinuous or irregular (e.g. have an irregularthickness), and the penetrated coating may not fill all of theinterstices of the mat, either of which may contribute to the relativelyhigh degree of air permeability of the facer.

In one or more embodiments, coating layers (e.g. layers 60 and 62), aswell as penetrated coating material (e.g. 66), derives from employing adouble-coated glass mat, which is a glass mat that includes coatingmaterial applied to both planar surfaces of the glass mat.

In one or more embodiments, the double-coated facer is characterized byan air permeability, which may also be referred to as porosity, asdetermined by ARC-WT-006 (which correlates to TAPPI T460om-96), of lessthan 300, in other embodiments less than 250, in other embodiments lessthan 200, in other embodiments less than 150, in other embodiments lessthan 100, in other embodiments less than 70, in other embodiments lessthan 50, in other embodiments less than 40, and in other embodimentsless than 30 Gurley seconds/300 cubic centimeters.

In one or more embodiments, the double-coated facer is characterized bya coating weight of greater than 500, in other embodiments greater than600, in other embodiments greater than 700, in other embodiments greaterthan 800, in other embodiments greater than 810, in other embodimentsgreater than 820, in other embodiments greater than 830, in otherembodiments greater than 840, in other embodiments greater then 850, inother embodiments greater then 860, in other embodiments greater 870, inother embodiments greater 880, in other embodiments greater than 890,and in other embodiments greater than 900 grams per square meter. In oneor more embodiments, the coating weight is less than 1000, in otherembodiments less than 950, and in other embodiments less than 920 gramsper square meter. As used herein, the term “coating weight” means theweight of the coating per area of the at least one glass fiber mat,which includes both coating layers as well as the penetrated coatingmaterial.

Foam Core

In one or more embodiments, body 31 includes a polyurethane orpolyisocyanurate cellular structure, which refers to an interconnectednetwork of solid struts or plates that form the edges and faces ofcells. These cellular structures may, in one or more embodiments, alsobe defined by a “relative density” that is less than about 0.8, in otherembodiments less than 0.5, and in other embodiments less than 0.3. Asthose skilled in the art will appreciate, “relative density” refers tothe density of the cellular material divided by that of the solid fromwhich the cell walls are made. As the relative density increases, thecell walls thicken and the pore space shrinks such that at some pointthere is a transition from a cellular structure to one that is betterdefined as a solid containing isolated porosity.

Despite the cellular nature of body 31, it has a relatively highdensity. In one or more embodiments, the density of body 31 is greaterthan 2.5 pounds per cubic foot (12.2 kg/m²), as determined according toASTM C303, in other embodiments the density is greater than 2.8 poundsper cubic foot (13.7 kg/m²), in other embodiments greater than 3.0pounds per cubic foot (14.6 kg/m²), and still in other embodimentsgreater than 3.5 pounds per cubic foot (17.1 kg/m²); on the other hand,in one or more embodiments, the density of body 31 may be less than 20pounds per cubic foot (97.6 kg/m²), in other embodiments less than 10pounds per cubic foot (48.8 kg/m²), in other embodiments less than 6pounds per cubic foot (29.3 kg/m²), in other embodiments less than 5.7pounds per cubic foot (28.8 kg/m²), in other embodiments less than 5.5pounds per cubic foot (28.3 kg/m²), in other embodiments less than 5.2pounds per cubic foot (27.8 kg/m²), in other embodiments less than 5.0pounds per cubic foot (27.3 kg/m²), and still in other embodiments lessthan 4.7 pounds per cubic foot (26.9 kg/m²).

In one or more embodiments, body 31 is characterized by an ISO Index, asdetermined by PIR/PUR ratio as determined by IR spectroscopy usingstandard foams of known index (note that ratio of 3 PIR/PUR provides anISO Index of 300), of at least 270, in other embodiments at least 285,in other embodiments at least 300, in other embodiments at least 315,and in other embodiments at least 325. In these or other embodiments,the ISO Index is less than 360, in other embodiments less than 350, inother embodiments less than 340, and in other embodiments less than 335.

BUR System BUR Sealant Material

As indicated above, the BUR system includes a sealant layer that derivesfrom a liquid sealant material; these systems may also be referred to ashot-mop systems. In one or more embodiments, the resultant sealant layeris a monolithic layer over the area to which it is applied. In one ormore embodiments, the sealant material is capable of creating a moistureresistant barrier that will meet the standards of ASTM E 108.

In one or more embodiments, the liquid sealant is a hot melt sealant,which includes those materials that can be liquefied at elevated, yetcommercially practical, temperatures. In one or more embodiments, theliquid sealants can be liquefied at temperature of at least 135° C., inother embodiments at least 155° C., and in other embodiments at least195° C. In one or more embodiments, the liquid sealants include thosematerials that can be liquefied at temperatures between 140° C. and 260°C. In one or more embodiments, the hot melt liquid sealant materialssolidify, at least to the extent that they can no longer be pouredand/or flow, at temperatures below 135° C., in other embodiments below120° C., and in other embodiments below 110° C. In one or moreembodiments, the liquid sealants are characterized, in their liquefiedstate (i.e. above the temperatures set forth above), by being pourable,flowable, and/or spreadable.

Practice of one or more embodiments of the present invention is notlimited by the selection of any particular hot melt sealant. In one ormore embodiments, the hot melt sealant is pitch, tar, asphalt, andcombinations thereof.

As the skilled person readily understands, pitch includes carbonaceousresidue left from the distillation of substances such as coal tar, pinetar, rosin, petroleum and fatty acids, or include naturally occurringsubstance having properties similar to the forgoing distillate residues.

The skilled person also understands that tar includes the residue leftfrom the destructive distillation of carbon rich materials such as coal,wood, and petroleum or as a naturally occurring substance havingproperties similar to the destructive distillation residues recited.

Further, the skilled person understands that asphalt includes a thickviscous mixture of hydrocarbons (bitumen) obtained chiefly as theresidue of petroleum distillation or as naturally occurring materials.The asphalt material may be derived from any asphalt source, such asnatural asphalt, rock asphalt, produced from tar sands, or petroleumasphalt obtained in the process of refining petroleum. In one or moreembodiments, the asphalt material may meet specific grade definitions.In other embodiments, asphalt binders may include a blend of variousasphalts not meeting any specific grade definition. This includesair-blown asphalt, vacuum-distilled asphalt, steam-distilled asphalt,cutback asphalt or roofing asphalt. Alternatively, gilsonite, natural orsynthetic, used alone or mixed with petroleum asphalt, may be selected.Synthetic asphalt mixtures suitable for use in the present invention aredescribed, for example, in U.S. Pat. No. 4,437,896. In one or moreembodiments, asphalts may include asphaltenes, resins, cyclics, andsaturates. The percentage of these constituents in the overall asphaltbinder composition may vary based on the source of the asphalt.Asphaltenes include black amorphous solids containing, in addition tocarbon and hydrogen, some nitrogen, sulfur, and oxygen. Trace elementssuch as nickel and vanadium may also be present. Asphaltenes aregenerally considered as highly polar aromatic materials of a numberaverage molecular weight of about 2000 to about 5000 g/mol, and mayconstitute about 5 to about 25% of the weight of asphalt. Resins (polararomatics) include dark-colored, solid and semi-solid, very adhesivefractions of relatively high molecular weight present in the maltenes.They may include the dispersing agents of peptizers for the asphaltenes,and the proportion of resins to asphaltenes governs, to a degree, thesol- or gel-type character of asphalts. Resins separated from bitumensmay have a number average molecular weight of about 0.8 to about 2kg/mol but there is a wide molecular distribution. This component mayconstitute about 15 to about 25% of the weight of asphalts. Cyclics(naphthene aromatics) include the compounds of lowest molecular weightin bitumens and represent the major portion of the dispersion medium forthe peptized asphaltenes. They may constitute about 45 to about 60% byweight of the total asphalt binder, and may be dark viscous liquids.They may include compounds with aromatic and naphthenic aromatic nucleiwith side chain constituents and may have molecular weights of 0.5 toabout 9 kg/mol. Saturates include predominantly the straight- andbranched-chain aliphatic hydrocarbons present in bitumens, together withalkyl naphthenes and some alkyl aromatics. The average molecular weightrange may be approximately similar to that of the cyclics, and thecomponents may include the waxy and non-waxy saturates. This fractionmay from about 5 to about 20% of the weight of asphalts. In these orother embodiments, asphalt binders may include bitumens that occur innature or may be obtained in petroleum processing. Asphalts may containvery high molecular weight hydrocarbons called asphaltenes, which may besoluble in carbon disulfide, pyridine, aromatic hydrocarbons,chlorinated hydrocarbons, and THF. Asphalts or bituminous materials maybe solids, semi-solids or liquids.

In one or more embodiments, the asphalt includes AC-5, AC-10 and AC-15.These asphalts typically contain about 40 to about 52 parts by weight ofaromatic hydrocarbons, about 20 to about 44 parts by weight of a polarorganic compound, about 10 to about 15 parts by weight of asphaltene,about 6 to about 8 parts by weight of saturates, and about 4 to about 5parts by weight of sulfur. Nevertheless, practice of the presentinvention is not limited by selection of any particular asphalt.

In one or more embodiments, the molecular weight of the aromatichydrocarbons present in asphalt may range between about 300 and 2000,while the polar organic compounds, which generally include hydroxylated,carboxylated and heterocyclic compounds, may have a weight averagemolecular weight of about 500 to 50,000. Asphaltenes, which aregenerally known as heavy hydrocarbons, are typically of a high molecularweight and are heptane insoluble. Saturates generally include paraffinicand cycloaliphatic hydrocarbons having about 300 to 2000 molecularweight.

In one or more embodiments, bitumens may be used. Bitumens are naturallyoccurring solidified hydrocarbons, typically collected as a residue ofpetroleum distillation. Gilsonite is believed to be the purest naturallyformed bitumen, typically having a molecular weight of about 3,000 withabout 3 parts by weight complexed nitrogen.

For purposes of this specification, these materials (i.e. the pitch,tar, asphalts) may be referred to collectively as asphalt or bitumen.Also, given the popularity of asphalt materials in these uses, referencemay be made to asphalt or bitumen, with the understanding that hot meltsealants may likewise employed unless otherwise stated. Reference mayalso be made to hot or molten asphalt with the understanding that theseterms refer to sealants generally, or asphalt specifically, above theirthreshold temperatures at which they are pourable, flowable, and/orspreadable.

In one or more embodiments, the liquid sealant material is an asphaltichot melt sealant that includes additional constituents as known in theart. For example, in one or more embodiments, the sealant includes apolymeric modifier, and therefore reference may be made tomodified-bitumen compositions. For example, the modified-bitumencompositions may include polymeric modifiers such asstyrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), as wellas hydrogenated verwsion thereof (e.g., SEPS and SEBS), atacticpolypropylene polymers, and ethylene/styrene copolymers or“interpolymers.”

Additionally, the asphaltic hot melt sealants useful in practice of thisinvention may also optionally include typical additives such as fireretardants, flame retardants, antioxidants, colorants, stabilizers,fillers, and mixtures thereof. In one or more embodiments, the asphaltcomposition meets the standards of ASTM D6152 or ASTM D 312.

BUR Protective Material

As explained above, the BUR may include a protective material over oneor more of the sealant layers. This protective material may includeweather-resistant particles. In one or more embodiments, these particlesserve not only a cosmetic purpose but also increase the weatherresistance of the hot melt sealant layer (i.e. the flood layer) of theBUR. In one or more embodiments, the weather resistant particles includewashed gravel (pebbles) or chipped marble.

BUR Fabric Reinforcement

In one or more embodiments, the fabric reinforcement may include atextile fabric, which may include woven and/or non-woven fabrics.Various fabric reinforcements are known in the art, and practice of thepresent invention is not necessarily limited by the selection of aparticular fabric. In one or more embodiments, the reinforcement may befabricated from fiberglass and/or synthetic yards or filaments.Exemplary synthetic yarns include those prepared from polyesters orpolyimides. In one or more embodiments, the fabrics meet the standardsof ASTM D2178.

Manufacture of Boards Laminator

The coverboards employed in embodiments of this invention can bemanufactured by using known techniques. In one or more embodiments, thecoverboards are made within a laminator construction line where foam isdeposited onto a continuously moving web of the facer described herein.Consistent with the teachings of this invention, the foam material isdeposited onto a planar surface of the facer and contacts the coatinglayer. It is believed that a technologically useful bond is createdbetween the foaming material and the coating material that forms thecoating layer and/or the penetrated coating. As the foam begins to rise,a second facer, which may also conform to the facers of this invention,is positioned above the foam and the composite is run through thelaminator. In positioning the top facer, the coating on the planarsurface of the second facer is also contacted to the foam.

Manufacture of Glass Mat

The glass fiber mat can be formed from any suitable process. Forexample, these glass fiber mats can be formed from an aqueous dispersionof glass fibers. In such process, a resin binder can be applied to a wetnon-woven web of fibers and after removing excess binder and water, theweb can be dried and heated to cure the resin binder to form thenon-woven mat product. Non-woven glass fiber mats can also be made bychopping dry strands of glass fibers bound together with a binder toform chopped strand, collecting the chopped strand on a moving conveyorin a random pattern, and bonding the chopped strand together at theircrossings by dusting a dry, powdered thermoplastic binder like apolyamide, polyester, or ethylene vinyl acetate on wetted choppedstrands followed by drying and curing the binder.

Application of Coating to Glass Mat

In one or more embodiments, a coating composition is applied to each ofthe planar surfaces of the glass mat. In other words, a first bindingcomposition may be applied to a first planar surface (which may bereferred to as an upper surface), and a second binding composition maybe applied to a second planar surface (which may be referred to as alower surface) opposite the first planar surface. The first and secondbinding compositions may be the same. Any method suitable for applying abinding composition or coating to a glass fiber mat or impregnating aglass fiber mat with a binding composition or coating may be used toapply the first binding composition to the upper surface of the at leastone glass fiber mat and the second binding composition to the lowersurface of the at least one glass fiber mat. The first and secondbinding composition can be applied by air spraying, dip coating, knifecoating, roll coating, or film application such as lamination/heatpressing. The ability to produce coated facers is known as described inU.S. Pat. Nos. 5,102,728, 5,112,678, and 7,138,346, which areincorporated herein by reference.

Manufacture of Foam Core

In general, and in a manner that is conventional in the art, the boardsof the present invention may be produced by developing or forming apolyurethane and/or polyisocyanurate foam in the presence of a blowingagent. The foam may be prepared by contacting an A-side stream ofreagents with a B-side stream of reagents and depositing the mixture ordeveloping foam onto a facer positioned on a laminator. As isconventional in the art, the A-side stream includes an isocyanate andthe B-side includes an isocyanate-reactive compound.

According to one or more aspects of this invention, the facer, which asdescribed above includes a coating layer on at least one planar surfaceof a fibrous mat, is positioned on the laminator so that the developingfoam is applied to the coating layer. As a result of this manufacturingtechnique, the interfacial region is created between the fibrous mat andthe foam core.

In one or more embodiments, processes for the manufacture ofpolyurethane or polyisocyanurate coverboards, including those having arelatively high density, are known in the art as described in U.S. Pat.Nos. 8,453,390 7,972,688, 7,387,753, 7,612,120, 6,774,071, 6,372,811,6,117,375, 6,044,604, 5,891,563, 5,573,092, and U.S. Publication Nos.2004/0102537, 2004/0109983, 2003/0082365, and 2003/0153656, which areincorporated herein by reference.

The A-side stream typically only contains the isocyanate, but, inaddition to isocyanate components, the A-side stream may containflame-retardants, surfactants, blowing agents and othernon-isocyanate-reactive components.

Suitable isocyanates are generally known in the art. Useful isocyanatesinclude aromatic polyisocyanates such as diphenyl methane, diisocyanatein the form of its 2,4′-, 2,2′-, and 4,4′-isomers and mixtures thereof,the mixtures of diphenyl methane diisocyanates (MDI) and oligomersthereof known in the art as “crude” or polymeric MDI having anisocyanate functionality of greater than 2, toluene diisocyanate in theform of its 2,4′ and 2,6′-isomers and mixtures thereof, 1,5-naphthalenediisocyanate, and 1,4′ diisocyanatobenzene. Exemplary isocyanatecomponents include polymeric Rubinate 1850 (Huntsmen Polyurethanes),polymeric Lupranate M70R (BASF), and polymeric Mondur 489N (Bayer).

The B-side stream, which contains isocyanate reactive compounds, mayalso include flame retardants, catalysts, emulsifiers/solubilizers,surfactants, blowing agents, fillers, fungicides, anti-staticsubstances, water and other ingredients that are conventional in theart.

An exemplary isocyanate-reactive component is a polyol. The terms polyolor polyol component include diols, polyols, and glycols, which maycontain water as generally known in the art. Primary and secondaryamines are suitable, as are polyether polyols and polyester polyols.Useful polyester polyols include phthalic anhydride based PS-2352(Stepen), phthalic anhydride based polyol PS-2412 (Stepen), teraphthalicbased polyol 3522 (Kosa), and a blended polyol TR 564 (Oxid). Usefulpolyether polyols include those based on sucrose, glycerin, and toluenediamine. Examples of glycols include diethylene glycol, dipropyleneglycol, and ethylene glycol. Suitable primary and secondary aminesinclude, without limitation, ethylene diamine, and diethanolamine. Inone embodiment a polyester polyol is employed. In one or moreembodiments, the present invention may be practiced in the appreciableabsence of any polyether polyol. In certain embodiments, the ingredientsare devoid of polyether polyols.

Catalysts are believed to initiate the polymerization reaction betweenthe isocyanate and the polyol, as well as a trimerization reactionbetween free isocyanate groups when polyisocyanurate foam is desired.While some catalysts expedite both reactions, two or more catalysts maybe employed to achieve both reactions. Useful catalysts include salts ofalkali metals and carboxylic acids or phenols, such as, for examplepotassium octoate; mononuclear or polynuclear Mannich bases ofcondensable phenols, oxo-compounds, and secondary amines, which areoptionally substituted with alkyl groups, aryl groups, or aralkylgroups; tertiary amines, such as pentamethyldiethylene triamine(PMDETA), 2,4,6-tris[(dimethylamino)methyl]phenol, triethyl amine,tributyl amine, N-methyl morpholine, and N-ethyl morpholine; basicnitrogen compounds, such as tetra alkyl ammonium hydroxides, alkalimetal hydroxides, alkali metal phenolates, and alkali metal acholates;and organic metal compounds, such as tin(II)-salts of carboxylic acids,tin(IV)-compounds, and organo lead compounds, such as lead naphthenateand lead octoate.

Surfactants, emulsifiers, and/or solubilizers may also be employed inthe production of polyurethane and polyisocyanurate foams in order toincrease the compatibility of the blowing agents with the isocyanate andpolyol components.

Surfactants may serve two purposes. First, they may help toemulsify/solubilize all the components so that they react completely.Second, they may promote cell nucleation and cell stabilization.Exemplary surfactants include silicone co-polymers or organic polymersbonded to a silicone polymer. Although surfactants can serve bothfunctions, a more cost effective method to ensureemulsification/solubilization may be to use enoughemulsifiers/solubilizers to maintain emulsification/solubilization and aminimal amount of the surfactant to obtain good cell nucleation and cellstabilization. Examples of surfactants include Pelron surfactant 9920,Goldschmidt surfactant B8522, and GE 6912. U.S. Pat. Nos. 5,686,499 and5,837,742 are incorporated herein by reference to show various usefulsurfactants.

Suitable emulsifiers/solubilizers include DABCO Kitane 20AS (AirProducts), and Tergitol NP-9 (nonylphenol+9 moles ethylene oxide).

Flame Retardants may be used in the production of polyurethane andpolyisocyanurate foams, especially when the foams contain flammableblowing agents such as pentane isomers. Useful flame retardants includetri(monochloropropyl) phosphate, tri-2-chloroethyl phosphate, phosphonicacid, methyl ester, dimethyl ester, and diethyl ester. U.S. Pat. No.5,182,309 is incorporated herein by reference to show useful blowingagents.

Useful blowing agents include isopentane, n-pentane, cyclopentane,alkanes, (cyclo) alkanes, hydrofluorocarbons, hydrochlorofluorocarbons,fluorocarbons, fluorinated ethers, alkenes, alkynes, carbon dioxide, andnoble gases. Depending on the required density of the board, the amountof blowing agent may need to be decreased up to about 95% from astandard formulation. The amount of water may also, optimally, bereduced. The less blowing agent used, the less catalyst is generallyused.

Installation of Roof System

In one or more embodiments, the roofing systems of the present inventionmay be installed using standard techniques with the exception that thecoverboards defined herein may be used as a protective barrier for anunderlying insulation layer.

For example, insulation board may be applied to an existing roof systemor roof deck using conventional techniques. These techniques may includemechanically fastening the insulation boards to the existing roof orroof deck, or these techniques may include the use of an adhesive tobond the insulation boards to the roof or roof deck.

In one or more embodiments, the coverboards defined herein are theninstalled over the insulation board layer. The coverboards may besecured to the insulation board exclusively, which can occur through theuse of an adhesive material to bond the coverboard directly to theinsulation layer (i.e. boards). Alternatively or in addition, thecoverboards can be mechanically fastened to the roof system, which mayinclude the use of mechanical fastening devices that penetrate not onlythe insulation layer but also the roof deck itself. As is known in theart, the coverboards may be arranged in a staggered pattern over theinsulation boards.

In one or more embodiments, the coverboards are installed so that thefacer having an interfacial region disposed between the facer and coreof coverboard is exposed for application of the hot sealant materialdirectly thereto. In other words, and according to one or moreembodiments of the invention, the planar surface of the coverboardhaving disposed thereon (which may also be referred to as securedthereto) a coated facer wherein the coating includes a layer disposedbetween the mat and the core of the board, is positioned upward and awayfrom the insulation layer. In one or more embodiments, the coverboardincludes facers on opposing planar surfaces of the board and both facershave an interfacial region disposed between the facers and the core ofthe board. In this latter situation, either side of the coverboard maybe exposed to the hot sealant to be applied and/or laid adjacent to theinsulation layer.

After application of the coverboards, which creates a layer ofcoverboards, which may also be referred to as a protective layer, overthe insulation boards or layer, a liquid sealant (e.g. hot meltasphaltic material) is applied over the coverboards. In one or moreembodiments, the hot melt sealant may be applied in a spreadable statedirectly to (i.e. over) the coverboards by pouring, spraying, brushing,rolling, squeegeeing, sponging, swabbing, and/or mopping. In one or moreembodiments, as indicated above with respect to the temperaturesprovided for the liquefied state of the hot melt material, theapplication of a hot melt sealant takes place above the thresholdliquefied temperature; e.g. application takes place in the temperaturerange of about 135+C. to about 260° C.

An accepted procedure for creating a BUR system includes applying aliquid layer of hot melt material and then applying a layer ofreinforcing material. This procedure may be alternately followed toachieve a plurality of plies of the bitumen/reinforcing material. Forexample, 3 or 4 plies may be applied. A final bitumen layer (flood coat)can then be applied over the plurality of plies. In one or moreembodiments, the reinforcing material is applied to the previouslydeposited hot melt layer prior to complete solidification of the hotmelt material.

After application of the flood coat, the protective material may beapplied. For example, pea gravel can be applied over the flood layer. Inone or more embodiments, the protective material is applied before thefinal hot melt sealant layer is completely solidified.

Advantages of Present Invention

As noted previously, the direct application of the hot melt sealant tothe roof underlying roof system is advantageously achieved withoutdeleterious impact on the insulation layer and the coverboard layer. Forexample, hot melt sealant, which may be at a temperature in of at least200° C. or at least 230° C., or at least 260° C. can applied directly tothe coverboards without deleteriously impacting the coverboard. Forexample, the boards are substantially free of delamination or blisteringduring installation or subsequent aging. Also, the boards aresubstantially free of deleterious bowing.

In order to demonstrate the practice of the present invention, thefollowing examples have been prepared and tested. The examples shouldnot, however, be viewed as limiting the scope of the invention. Theclaims will serve to define the invention.

EXAMPLES

Sample test roofing systems were prepared by employing the followingmethod. The samples were tested on test roof systems that included awood deck supported above the ground by a stand. Variouspolyisocyanurate foamed construction boards were installed over the wooddeck and then an asphalt coating was applied over the constructionboard. The condition of the asphalt coating and/or sample roof wasobserved after application. Table I below details the type ofconstruction board employed as well as the observations made.

The construction boards included the following. As detailed in Table I,the boards included a “high density” foam core wherein the density ofthe foam core was about 5 pounds per cubic foot or a “low density” foamcore wherein the density of the foam core was about 1.6 pounds per cubicfoot. The thickness of the foam layer is also detailed in Table I. Also,as detailed in Table I, three types of facers were disposed on the highdensity or low density boards. The first was a glass-reinforced paperfacer of the type used on conventional polyisocyanurate board. Forpurposes of the Table, these facers have been designated as “paper.” Thesecond was a standard glass facer of the type used on conventionalpolyisocyanurate insulation or cover boards. While facers of this natureoften include a coating, the coating does not form an interfacial regionbetween the mat and foam as contemplated by the present invention. Forpurposes of the Table, these facers have been designated as “glass.” Thethird was a coated glass facer of the type described in the presentinvention wherein an interfacial region exists between the mat and thefoam. For purposes of the Table, these facers have been designated as“coated glass.”

The coverboards were all the hot mopped into place using Type IVasphalt. The Type IV asphalt was generally maintained at a temperatureabove about 475° F. during application. The hot asphalt was firstapplied as a ply coat followed by application of a top coat.

After about an hour following application of the hot asphalt,observations were made. Facer delamination and the formation of bubbleswere recorded as set forth in Table I. The amount of bubbles were givena subjective rating on a 1 to 10 scale, a 1 signifying the greatestamount of bubble forming on the surface and 10 signifying the leastamount of bubbles forming on the surface. Five different people assessedthe amount of bubbles formed and the average of those five rankings isset forth in the Table.

TABLE Core Perforation Type of Facer Average Bubble Sample Facer DensityThickness Y/N Treatment Delamination Rating 1 Paper 1.6 0.5 Yes None No5.0 2 Glass 1.6 0.5 Yes None No 3.3 3 Paper 1.6 0.5 No None Yes 4.8 4Glass 1.6 0.5 No None Yes 2.3 5 Paper 5 0.5 Yes None No 4.5 6 Glass 50.5 Yes None No 2.3 7 Coated 5 0.5 Yes None No 3.5 Glass 8 Paper 5 0.5No None No 4.0 9 Glass 5 0.5 No None No 1.5 10 Coated 5 0.5 No None No7.8 Glass 11 Paper 1.6 1 Yes None Yes 4.3 12 Glass 1.6 1 Yes None No 3.013 Coated 1.6 1 Yes None No 3.8 Glass 14 Paper 1.6 1 No None Yes 4.0 15Glass 1.6 1 No None Yes 2.3 16 Coated 1.6 1 No None yes 7.0 Glass 17Paper 5 1 Yes None No 7.0 18 Glass 5 1 Yes None No 3.5 19 Coated 5 1 yesNone No 7.5 Glass 20 Paper 5 1 No None Yes 8.5 21 Glass 5 1 No None No3.5 22 Coated 5 1 No None No 7.3 Glass

Various modifications and alterations that do not depart from the scopeand spirit of this invention will become apparent to those skilled inthe art. This invention is not to be duly limited to the illustrativeembodiments set forth herein.

What is claimed is:
 1. A roof system comprising: (i) a roof deck; (ii)an insulation layer; (iii) a coverboard disposed over said insulationlayer, where said coverboard includes a foam core and a facer includinga fibrous mat and an interfacial region disposed between said core andsaid mat; and (iv) a layer of asphalt.
 2. The roof system of claim 1,where said insulation layer includes foamed polyurethane,polyisocyanurate, polystyrene, or a mixture of two or more thereof. 3.The roof system of claim 1, where said foam core includespolyisocyanurate foam.
 4. The roof system of claim 1, where said foamcore of said coverboard includes polyisocyanurate foam having a density,as defined by ASTM C303, of greater than 2.5 pounds per cubic foot. 5.The roof system of claim 1, where said foam core of said coverboardincludes polyisocyanurate foam having a density, as defined by ASTMC303, of greater than 3.5 pounds per cubic foot.
 6. The roof system ofclaim 1, where said foam core of said coverboard includespolyisocyanurate foam having a density, as defined by ASTM C303, of lessthan 5.5 pounds per cubic foot.
 7. The roof system of claim 1, where thelayer of asphalt is applied to said coverboard as a hot melt.
 8. Theroof system of claim 1, where said interfacial region is a polymericinterfacial region.
 9. The roof system of claim 1, where said mat is aglass mat.
 10. The roof system of claim 1, where the build-up roofsystem includes at least one layer of sealant material.
 11. A method forinstalling a roof system, the method comprising: (i) applying a layer ofcoverboards to a layer of insulation, where the coverboards include afoam core and a facer including a fibrous mat and an interfacial regiondisposed between said core and said mat; and (ii) applying a liquefiedhot-melt sealant directly to the coverboard.
 12. The roof system ofclaim 11, where said insulation layer includes foamed polyurethane,polyisocyanurate, polystyrene, or a mixture of two or more thereof. 13.The roof system of claim 11, where said foam core includespolyisocyanurate foam.
 14. The roof system of claim 11, where said foamcore of said coverboard includes polyisocyanurate foam having a density,as defined by ASTM C303, of greater than 2.5 pounds per cubic foot. 15.The roof system of claim 11, where said foam core of said coverboardincludes polyisocyanurate foam having a density, as defined by ASTMC303, of greater than 3.5 pounds per cubic foot.
 16. The roof system ofclaim 11, where said foam core of said coverboard includespolyisocyanurate foam having a density, as defined by ASTM C303, of lessthan 5.5 pounds per cubic foot.
 17. The roof system of claim 11, wheresaid step of applying a liquefied hot-melt sealant includes applying hotasphalt.
 18. The roof system of claim 11, where said interfacial regionis a polymeric interfacial region.
 19. The roof system of claim 11,where said mat is a glass mat.
 20. The roof system of claim 11, wherethe roof system includes at least one layer of sealant material.